DIAGNOSIS An artifact of the VA panel's rapid pixel response (GtG) at high refresh rates. Sometimes called "scan line inversion" or "corduroy effect."
FIX Adjust the Response Time setting. In the OSD, go to Game > Response Time. Change from 'Faster' or 'Fastest' down to 'Standard.' This reduces overdrive aggression and eliminates the artifact for most users.
IF THAT DIDN'T WORK Change the Black Equalizer setting. Go to Game > Black Equalizer. Set it to a lower value, like 10-12. High values can exacerbate this visual noise in mid-tone colors.
HEADS UP This is a known characteristic of this panel, not a defect. It is most visible in shades of grey, orange, and brown. It does not affect performance or longevity.